Fix promotion sweep of black Pawns in Shogi

The wrap-around when we run past white King should not be done in
toggle mode, where it is guaranteed we won't run out of range.

diff --git a/backend.c b/backend.c
index 5b66016..4974fed 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -5399,8 +5399,8 @@ Sweep (int step)
        if(step && !(toggleFlag && Partner(&promoSweep))) promoSweep -= step;
        if(promoSweep == EmptySquare) promoSweep = BlackPawn; // wrap
        else if((int)promoSweep == -1) promoSweep = WhiteKing;
-       else if(promoSweep == BlackPawn && step < 0) promoSweep = WhitePawn;
-       else if(promoSweep == WhiteKing && step > 0) promoSweep = BlackKing;
+       else if(promoSweep == BlackPawn && step < 0 && !toggleFlag) promoSweep = WhitePawn;
+       else if(promoSweep == WhiteKing && step > 0 && !toggleFlag) promoSweep = BlackKing;
        if(!step) step = -1;
     } while(PieceToChar(promoSweep) == '.' || PieceToChar(promoSweep) == '~' || promoSweep == pawn ||
            !toggleFlag && PieceToChar(promoSweep) == '+' || // skip promoted versions of other